It would be nice if global shortcuts could be disabled for some apps.
Eg: I use alt-cmd-1 as a divvy shortcut, but this is also the shortcut used in Word and Google docs to change style to "Heading 1".
(Google docs is run by Google Chrome: it might be hard to disable the global shortcut for a specific site.)

NB: on windows, you can use autohotkey to set a different behaviour to the shortcut, depending on the app or title of the front window.